Help me choose
A stronger Pool Express option
Dolphin Nautilus AG and Dolphin S400 are compared feature by feature below. For a stronger Pool Express option, consider Dolphin Cayman. Inground and above-ground pools up to 40 ft that need floor and wall cleaning.
Nautilus
Dolphin Nautilus AG
Above-ground and small inground pools up to 30 ft that need the floor vacuumed.
S-Line
Dolphin S400
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
What we recommend instead
Dolphin Cayman
Inground and above-ground pools up to 40 ft that need floor and wall cleaning.
$1,079
Buy Dolphin CaymanDolphin Nautilus AG or Dolphin S400: our take
Dolphin Nautilus AG and Dolphin S400 are compared on pool fit, cleaning reach, debris handling, controls and ownership details. The recommendation is based on the job the robot must do—not a simple feature count.
Pool fit and cleaning reach
Dolphin Nautilus AG is intended for above-ground pools, while Dolphin S400 is intended for inground pools. Dolphin Nautilus AG is rated for pools up to 30 ft; Dolphin S400 is rated up to 50 ft. Dolphin Nautilus AG cleans floor; Dolphin S400 cleans floor, walls, and waterline. Dolphin Nautilus AG lists 1 active brush and CleverClean navigation. Dolphin S400 lists 2 active brushes and CleverClean navigation.
Filtration and debris
Dolphin Nautilus AG includes Basket; Dolphin S400 includes Basket and UltraFilter. Dolphin S400 has the clearer documented edge for fine silt, pollen and sand.
Controls and day-to-day ownership
Dolphin Nautilus AG provides one-touch starts and power-supply controls; Dolphin S400 provides a weekly timer and smartphone control. Dolphin Nautilus AG uses continuous corded power, while Dolphin S400 uses a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Nautilus AG is listed at $568 and Dolphin S400 at $1,799; Dolphin Nautilus AG is $1,231 less. Dolphin Nautilus AG lists a 1-year warranty compared with 2 years for Dolphin S400. Dolphin Nautilus AG and Dolphin S400 each have a specific fit, but neither is the Pool Express pick for this job. Our better alternative is Dolphin Cayman. Inground and above-ground pools up to 40 ft that need floor and wall cleaning.
Feature check: what each robot actually has
A green check means the feature is documented as included. A red X means it is documented as absent. A dash means the source does not make the feature clear.
| Feature | Dolphin Nautilus AG | Dolphin S400 |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | No | YesEdge |
| Scrubs the waterline | No | YesEdge |
| Fine-debris filter included | No | YesEdge |
| Large-debris filter | Yes | Yes |
| Automatic scheduling | No | YesEdge |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | No | YesEdge |
| 3-year warranty | No | No |
| No recharging between cycles | Yes | Yes |
| Built-in UV-C water treatment | No | No |
Unknown is not treated as “no.” Specifications come from the product pages, current catalog records and manufacturer material collected for this site.
Where Dolphin Nautilus AG stands out
Dolphin Nautilus AG is the better fit for shoppers prioritizing the lower $568 starting price.
- Is listed $1,231 lower
- Cleans the pool floor
Where Dolphin S400 stands out
Dolphin S400 is the better fit for pools up to 50 ft.
- Cleans the floor, walls and waterline instead of stopping below the tile line
- Includes filtration for sand, pollen and other fine debris
- Uses 2 active brushes instead of 1
- Can start on a weekly schedule without a manual launch before every cycle
Dolphin Nautilus AG vs Dolphin S400 specifications
Use pool fit first. Price and app control do not make up for a robot that cannot cover the length or surfaces you need cleaned.
| Specification | Dolphin Nautilus AG | Dolphin S400 |
|---|---|---|
| Best fit | Above-ground and small inground pools up to 30 ft that need the floor vacuumed. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $568 | $1,799 |
| Pool type | Above-ground | Inground |
| Maximum pool length | Up to 30 ft | Up to 50 ft |
| Cleaning coverage | Floor | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket | Basket, UltraFilter |
| Scheduling | One-touch start | Weekly schedule + app |
| App and remote | Power-supply controls | App control |
| Cable | Not listed | 60 ft with anti-tangle swivel |
| Robot weight | 14.6 lb | Not listed |
| Warranty | 1 years | 2 years |
Consider the stronger Pool Express option
Dolphin Nautilus AG and Dolphin S400 are compared feature by feature below. For a stronger Pool Express option, consider Dolphin Cayman. Inground and above-ground pools up to 40 ft that need floor and wall cleaning.
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